The simple way to play is to use the soft side of Velcro. There’s lots of things you can put under it to get a little clearance, piece of popsickle stick, weedeater string, etc. I use a piece of zip tie cut to fit quite often. You have to replace the Velcro some but once you figure out what you want you can use leather and attach it with rubber cement. Ralph

Lots of things to consider here. First, if you handle is thick enough you can use a round file to cut a groove to help hold the arrow in place and for arrow clearance. Then just something to hold the arrow from below, as Ralph suggests. You can easily carve a little shelf and glue it on below the handle notch, or drill a small shallow hole not too deep into the handle and glue in a peg for an arrow shelf. Thing about just a shelf with no handle groove for the arrow is that you’re pretty much required to cant the bow to keep the arrow from falling off. Even when using your finger for a shelf as per traditional longbow shooting style, there’s enough friction there that you can shoot with the bow vertical and not lose the arrow. Not so with a shelf. I never shoot better with a Hill style longbow than when shooting off a finger, or “the knuckles” as we say. What does help is to have some sort of a reference to help you get your hand in exactly the same location every time.

I have seen the end of a cow or buffalo horn cut and shaped to fit the curve of the handle then glued in place. You could also use a contrasting piece of wood.

I would use a small piece of leather kinda like a flipper and then wrap the handle to cover the rest. If not you could find a small piece of horn or wood for a rest then put velcro on it.

Hope this helps